JP6686948B2 - Vehicle substructure - Google Patents

Description

  The present invention relates to a vehicle substructure.

  2. Description of the Related Art In a battery-equipped vehicle such as an electric vehicle, a plurality of batteries are mounted below a passenger compartment floor in a battery case. Therefore, there is a portion having a large weight (mass) below the passenger compartment. Therefore, when the vehicle has a frontal collision with an obstacle or the like, there is a problem that a large inertial force acts on the battery unit and the vehicle compartment located above the battery unit and the vehicle compartment is easily deformed.

  Therefore, in such a battery-equipped vehicle, various proposals have been made to reduce the impact force acting on the vehicle interior. For example, Patent Literature 1 discloses a shock absorbing floor structure in an electric vehicle in which a frame having a U-shaped cross section having a longitudinal shape in the front-rear direction is extended to the front of the front wheels of the vehicle under the floor. Then, a structure has been proposed in which the battery is not housed in a certain range from the front end (front end) of the frame, and the portion is used as a shock absorbing portion at the time of a frontal collision.

  Further, in Patent Document 2, in an electric vehicle in which a battery unit is mounted on a lower portion of a passenger compartment floor, a front end portion of a frame member that constitutes a support member that supports a battery module of the battery unit and extends in the vehicle front-rear direction , A battery mounting structure coupled to a suspension cross member has been proposed. With such a structure, a structure has been proposed in which the inertial force of the battery unit at the time of a frontal collision is transmitted to the suspension member from the coupling portion, thereby improving the shock absorbing performance.

JP 2012-201284 A JP, 2012-91636, A

  However, in the shock absorbing floor structure disclosed in Patent Document 1, it is considered that it is difficult to sufficiently secure the shock absorbing performance of the frame because the frame which is continuous in a straight line in the vehicle front-rear direction is formed. The battery (battery cell) itself may be damaged.

  Further, in the case of the battery mounting structure described in Patent Document 2, in order for the suspension member to receive the inertial force acting from the battery module in the case of a frontal collision, it is necessary to separately provide a structure for absorbing the inertial force by the suspension member.

  In view of the above facts, the present invention has an object to provide a vehicle lower structure that has improved shock absorption performance with a simple structure in a vehicle in which a battery is stored under the floor.

  The vehicle lower structure according to the present invention according to claim 1 is disposed on a vehicle lower side of a vehicle compartment floor, and has a bottom wall and a peripheral wall extending from a peripheral portion of the bottom wall to a vehicle upper side. A case main body capable of accommodating a battery therein, and a front extension part integrally formed with the case main body on the vehicle front side of the case main body from the peripheral wall on the vehicle front side of the case main body, A shock absorber that extends in the vehicle front-rear direction, has a rear end connected to a vehicle front side portion of the front extension, and is deformed by input of a collision load from the vehicle front.

  In the vehicle lower portion structure according to the present invention as set forth in claim 1, the case main body having the bottom wall and the peripheral wall is disposed on the vehicle lower side of the passenger compartment floor, and the battery is housed therein. Further, on the vehicle front side of the case body, a front extension portion is formed integrally with the case body from a peripheral wall of the case body on the vehicle front side. On the vehicle front side of the front extension portion, there is a shock absorbing portion that extends in the vehicle front-rear direction and has a rear end portion connected to the vehicle front side of the front extension portion.

  Therefore, when the vehicle collides with the front, the collision load is first input to the impact absorbing portion. As a result, the shock absorbing portion is deformed and the collision energy is absorbed. When the impact energy cannot be absorbed due to the deformation of the impact absorbing portion, the front extension portion is deformed and the impact energy due to the frontal collision is absorbed. This prevents or suppresses deformation of the case body or damage to the battery housed inside the case body.

  Further, since the front extension part is provided integrally with the case body, the structure is simple (the workability of assembling is good).

  A vehicle lower structure according to a second aspect of the present invention is the vehicle lower structure according to the first aspect of the present invention, wherein the case body extends in the vehicle front-rear direction on both sides of the case body in the vehicle width direction. Connected to Rocca.

  In the vehicle lower part structure according to the present invention as set forth in claim 2, the case body is connected to the pair of rockers extending in the vehicle front-rear direction at both ends in the vehicle width direction of the case body. Therefore, the collision load acting on the case main body containing the battery due to the frontal collision of the vehicle is distributed to the rocker, so that the deformation of the case main body or the damage of the battery contained inside the case main body is further prevented or suppressed. To be done.

  A vehicle lower structure according to a third aspect of the present invention is the vehicle lower structure according to the first or second aspect of the present invention, wherein a pair of left and right suspension lower arms are provided at both ends in the vehicle width direction of the front extending portion. Is swingably attached.

  In the vehicle lower structure according to the third aspect of the present invention, a pair of left and right suspension lower arms are attached to both ends of the front extension in the vehicle width direction. Therefore, the existing suspension member that supports the front suspension is not required, and the vehicle body structure is simplified. Further, the front suspension (suspension lower arm) can be integrated with the front extension portion (case body portion) to form a module.

  Further, the front extension portion is deformed at the time of a frontal collision of the vehicle, and the front suspension attached to the front extension portion is also deformed to absorb the collision energy. As a result, the amount of collision energy absorbed on the front side of the case body increases, and deformation of the case body or damage to the battery housed inside the case body is further prevented or suppressed.

  A vehicle lower part structure according to a fourth aspect of the present invention is the vehicle lower part structure according to any one of the first to third aspects of the present invention, wherein the impact absorbing portion is a pair of left and right extending in the vehicle front-rear direction. And an under-reinforce connecting the front ends of the under-member.

  In the vehicle lower portion structure according to the present invention as set forth in claim 4, a pair of left and right under members having a shock absorbing portion arranged in front of the front extension portion in the vehicle extends in the vehicle front-rear direction, and front ends of the under members. Includes connecting reinforcements. Therefore, the collision energy at the time of frontal collision can be absorbed by the deformation of the lower reinforcement and the under member at the time of frontal collision of the vehicle.

  The vehicle lower structure according to the present invention described in claims 1 to 4 can improve the shock absorbing performance at the time of a frontal collision of the vehicle with a simple structure.

It is a schematic diagram which shows the vehicle lower part structure seen from the vehicle side part which concerns on one Embodiment of this invention. It is a perspective view showing a partially omitted vehicle lower part structure concerning one embodiment of the present invention. It is the sectional view on the AA line of FIG.

  The vehicle lower structure according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 3. The vehicle up-down direction upper side is indicated by an arrow UP, the vehicle front-rear direction front side is indicated by an arrow FR, and the vehicle width direction right side is indicated by an arrow RH. Further, in FIG. 2, the side member 14 and the rocker 122 are not shown.

(Structure of vehicle front)
First, a vehicle 12 to which the vehicle lower structure 10 is applied will be described.

  As shown in FIG. 1, the vehicle 12 is an electric vehicle, and includes a side member 14 that is a vehicle frame member, and a battery pack 16 supported by the side member 14.

  As shown in FIG. 1, the side members 14 (only one is shown) are a pair of left and right vehicle frame members that extend from the front end to the rear end of the vehicle on both sides in the vehicle width direction of the vehicle. Each of the side members 14 extends in the vehicle front-rear direction on the vehicle front side, and continuously extends from the rear end of the front side member 18 to the vehicle rear side at a position lower than the front side member 18 by one step. However, it has a floor under reinforcement 20 that supports a floor panel 120, which will be described later, and a rear side member 22 that extends continuously from the rear end of the floor under reinforcement 20 to the vehicle rear side at a position higher than the floor under reinforcement 20. .

  An upper reinforcement 26 is attached to the front end of the front side member 18 via a crash box 24. The upper reinforcement 26 extends in the vehicle width direction and connects the front ends of the pair of front side members 18 (crash box 24).

  Similarly, the rear end of the rear side member 22 is also connected to the other rear side member 22 by the reinforcement 28.

  As shown in FIG. 2, the battery pack 16 includes a case lower 30 and a case upper 32 that is a lid for the battery module accommodating portion of the case lower 30.

  The case lower 30 includes a case main body 34 having a rectangular shape in plan view and an open upper portion, and a front extension portion formed on the front side of the case main body 34 and having a rectangular shape in plan view and an open upper portion. 36, and a box-shaped rear extension 38 formed on the rear side of the case body 34 and having a rectangular shape in plan view and an open top. The case lower 30 has a case body 34, a front extension 36, and a rear extension 38 that are integrally formed by casting.

  The case body 34 has a rectangular shape in plan view by surrounding the bottom wall 40 with a front wall 42, a rear wall 44, a left wall 46, and a right wall 48. The battery module 50 is housed inside the case body 34.

  Screw holes 52 for mounting the case upper 32 are formed on the upper surfaces of the front wall 42, the rear wall 44, the left wall 46, and the right wall 48 of the case main body 34. In addition, in FIG. 2, in order to avoid complexity of the drawing, only one screw hole 52 is denoted by a reference numeral, and the others are omitted.

  Further, a plurality of mounting portions 54 for mounting the case main body portion 34 to the floor under reinforcement 20 are formed on the outer surfaces of the left wall 46 and the right wall 48 at predetermined intervals in the vehicle front-rear direction. As shown in FIGS. 1 and 2, the mounting portion 54 has a rectangular upper wall 56 in a plan view and a pair of side walls 58 extending downward from the front end and the rear end of the upper wall 56, respectively. As shown in FIGS. 2 and 3, the side wall 58 is formed such that the width in the vertical direction is wide on the left wall 46 and the right wall 48 sides, and the width in the vertical direction becomes narrower toward the outer side in the vehicle width direction.

  Further, an insertion hole 60 for inserting a fastener is formed in the upper wall 56. In addition, in FIGS. 1 and 2, in order to avoid complexity of the drawings, reference numerals are given to components only at one mounting portion 54, and the other components are omitted.

  The front extension part 36 is formed integrally with the case body 34 on the vehicle front side of the case body 34 (front wall 42). The front extension 36 is formed in a rectangular shape in plan view by surrounding the bottom wall 62 with the front wall 64, the left wall 66, the right wall 68, and the front wall 42 of the case body 34. No battery module is arranged inside the front extension 36.

  In addition, as shown in FIG. 2, the width of the front extension portion 36 in the vehicle width direction is set narrower than the width of the case main body portion 34 in the vehicle width direction in order to attach lower arms 80A and 80B to be described later. Has been done.

  Further, brackets 70A and 70B for mounting the front side member 18 are provided on the front end portions of the upper surfaces of the left wall 66 and the right wall 68, respectively. The bracket 70A is formed by a leg portion 72A that extends obliquely upward and upward in the vehicle width direction (upper left side) from the upper surface of the left wall 66, and extends outward (left side) in the vehicle width direction from the upper ends of the leg portions 72A. And a mounting portion 74A. An insertion hole 76A for a fastener for fastening to the front side member 18 is formed in the mounting portion 74A. Therefore, as shown in FIG. 1, the mounting portion 74A is brought into contact with the lower surface of the front side member 18, and the front side member 18 and the bracket 70A are fastened by a fastener (not shown) inserted in the insertion hole 76A. That is, the front extension 36 is fastened to the front side member 18.

  Since the bracket 70B is bilaterally symmetrical to the bracket 70A, the same components as those of the bracket 70A are denoted by the same reference numerals as those of the bracket 70A, and the detailed description thereof will be omitted.

  A lower arm 80A is supported on the lower portion of the left wall 66 so as to be vertically swingable about a shaft extending in the vehicle front-rear direction and supported by the left wall 66. A lower arm 80B is similarly supported on the lower portion of the right wall 68. That is, the front extension 36 is integrated with the front suspension including the lower arms 80A and 80B.

  Further, as shown in FIGS. 1 and 2, a steering gear 82 extending in the vehicle width direction is attached to the upper portion of the front wall 64.

  The rear ends of the pair of left and right under members 84 are connected to the lower portion of the front wall 64.

  Each under member 84 extends in the vehicle front-rear direction on the vehicle front side of the front extension 36, and its front ends are connected to each other by a lower reinforcement 86 extending in the vehicle width direction. The under member 84 and the lower reinforcement 86 are configured to be more easily deformed than the front extension 36 when a collision load is input from the front of the vehicle.

  As shown in FIG. 2, the rear extension 38 is formed integrally with the case main body 34 on the vehicle rear side of the case main body 34 (rear wall 44). The rear extension 38 is rectangular in plan view by surrounding the bottom wall 88 with the left wall 90, the right wall 92, the rear wall 94, and the rear wall 44 of the case body 34. No battery module is disposed inside the rear extension 38.

  Further, as shown in FIG. 2, the width of the rear extension portion 38 in the vehicle width direction is formed narrower than the width of the case main body portion 34 in the vehicle width direction.

  Further, brackets 96A and 96B for mounting the rear side member 22 are provided at the rear end portions of the upper surfaces of the left wall 90 and the right wall 92, respectively. Like the brackets 70A and 70B, the brackets 96A and 96B have leg portions 100A and 100B and mounting portions 102A and 102B in which insertion holes 104A and 104B are formed. Then, the brackets 96A and 96B are fastened to the rear side member 22 by the fasteners inserted through the insertion holes 104A and 104B. That is, the rear extension 38 is fastened to the rear side member 22.

  Further, constituent parts of a rear suspension (not shown) are attached to the left wall 90 and the right wall 92, and the rear suspension and the rear extension part 38 are integrated.

  The case upper 32 covers the case body 34 of the case lower 30. The case upper 32 has a box-shaped lid body 108 that is rectangular in a plan view and has an opening at the bottom, and a flange 110 that extends outward from the opening of the lid body 108. In the flange portion 110, a plurality of insertion holes 112 for fasteners are formed at positions facing the screw holes 52 when the flange portion 110 is placed on the case main body 34. Therefore, by mounting the flange portion 110 of the case upper 32 on the upper portion of the case body portion 34, inserting the fastener through the insertion hole 112 of the flange portion 110, and screwing the fastener into the screw hole 52 of the case body portion 34, The case upper 32 is fixed to the case body 34.

  The battery pack 16 is disposed below the floor panel 120, as shown in FIG. The floor panel 120 is joined to rockers 122 extending in the vehicle front-rear direction at both vehicle width direction ends of the vehicle compartment. Note that the rocker 122 has a closed cross section formed by joining flange portions of a rocker inner 124 arranged on the inner side in the vehicle width direction and a rocker outer 126 arranged on the outer side in the vehicle width direction. The floor panel 120 is supported from below by a floor under reinforcement 20 having a hat-shaped cross section. The floor under reinforcement 20 has a hat-shaped cross section with an opening at the top, and flange portions 128 at both ends are joined to the floor panel 120 to form a closed cross section. Further, the bottom wall 130 of the floor under reinforcement 20 is formed with an insertion hole for a fastener (bolt 132). At the time of assembly, the bolt 132 is inserted from the insertion hole side of the bottom wall 130 of the floor under reinforcement 20 into the insertion hole 60 of the mounting portion 54 of the case main body 34, and is fastened with the nut 134 from the lower side. The battery pack 16 (case main body 34) is fastened. That is, the battery pack 16 (case body portion 34) is connected to the rocker 122 via the floor under reinforcement 20 and the floor panel 120.

  In FIG. 1, reference numeral 136 indicates a motor, and reference numeral 138 indicates an upper monocoque body.

(Action)
The operation of the vehicle substructure 10 thus configured will be described.

  When the vehicle 12 collides frontally with an obstacle or the like, a collision load is first input to the lower reinforcement 86 and the under member 84 from the front of the vehicle, and the lower reinforcement 86 and the under member 84 are deformed. Thereby, the collision energy due to the frontal collision is absorbed. When the collision energy cannot be completely absorbed due to the deformation of the lower reinforcement 86 and the under member 84, the front extension portion 36 to which the rear end of the under member 84 is connected and the front portion attached to the front extension portion 36. The collision energy is absorbed by the deformation of the suspension components.

  As described above, at the time of a frontal collision of the vehicle, the collision energy is sufficiently absorbed by the deformation of the lower reinforcement 86, the under member 84, the front extension portion 36, and the components of the front suspension attached to the front extension portion 36. The deformation of the case body 34 and the damage of the battery module 50 housed in the case body 34 are prevented or suppressed.

  In the case of a slight frontal collision, only the under member 84 and the lower reinforcement 86 are deformed. Since the under member 84, the lower reinforcement 86 and the battery pack 16 (the case lower 30) are separated, only the under member 84 and the lower reinforcement 86 need to be replaced after a collision, which is excellent in serviceability.

  Furthermore, since the battery pack 16 (the case body portion 34 of the case lower 30) is connected to the rocker 122 via the floor under reinforcement 20 and the floor panel 120, a collision input to the battery pack 16 (the case body portion 34). The load is distributed to the rocker 122. Therefore, the deformation of the case main body 34 and the damage of the battery module 50 housed in the case main body 34 during the frontal collision of the vehicle are further prevented or suppressed.

  Further, as shown in FIG. 3, the battery pack 16 has the case main body 34 disposed between the pair of floor under reinforcements 20 to secure a wide width in the vehicle width direction, so that the battery of a predetermined capacity is provided. The module 50 can be housed in the case body 34.

  On the other hand, the front extension portion 36 is formed to have a width in the vehicle width direction smaller than that of the case main body portion 34, so that the lower arms 80A and 80B can be attached to the left wall 66 and the right wall 68. Since the rear extension 38 is also formed in the same manner as the front extension 36, the components of the rear suspension can be attached to the left wall 90 and the right wall 92.

  Thus, since the front extension (36) supports the front suspension (lower arms 80A, 80B), the existing suspension member can be eliminated. That is, the front extension 36 provided in the battery pack 16 for absorbing the collision energy at the time of frontal collision supports the front suspension (also functions as a suspension member). Therefore, the structure of the vehicle body is simplified. The same applies to the rear extension 38.

  Further, the front extension 36 and the rear extension 38 allow the front suspension and the rear suspension to be integrated with the battery pack 16 into a module. Therefore, since the vehicle is configured by mounting the upper monocoque body 138 on the upper part of the battery pack 16 in which the front suspension and the rear suspension are integrated (modularized), the upper monocoque body 138 having a different design is replaced. It is possible to manufacture vehicles of different vehicle types.

  In addition, since the front extension 36 does not house the battery module 50 and the like inside as compared to the case body 34, the front extension 36 is compared with the case body 34 in which the battery module 50 is housed during a frontal collision. And easily deformed.

  Further, although the front extension portion 36 is formed integrally with the case main body portion 34, since the front extension portion 36 is partitioned by the front wall 42, the deformation of the front extension portion 36 affects the case main body portion 34. Are prevented or suppressed. Therefore, the deformation of the case main body 34 and the damage of the battery module 50 housed in the case main body 34 due to the frontal collision are further prevented or suppressed.

[Other]
In the present embodiment, the front extension 36 has a rectangular shape in plan view and a box shape with an open top, but the shape is not limited to this. The shape is not particularly limited as long as it is more likely to be deformed than the case main body portion 34 at the time of a frontal collision and is less likely to be deformed than the lower reinforcement 86 and the under member 84.

  Further, in the present embodiment, the lower reinforcement 86 and the under member 84 are provided as the shock absorbing portion, but the present invention is not limited to this. There is no particular limitation as long as it is disposed on the vehicle front side of the front extension portion 36 and is more easily deformed than the front extension portion 36 in a frontal collision.

  Further, in the present embodiment, the vehicle substructure 10 is applied to the vehicle 12 which is an electric vehicle, but the present invention is not limited to this. As long as the battery pack 16 is mounted below the floor panel 120, it can be applied to a vehicle such as a hybrid vehicle (HV vehicle).

10 Vehicle Lower Structure 34 Case Main Body 36 Front Extension 40 Bottom Wall 42 Front Wall (Peripheral Wall)
44 Rear wall (peripheral wall)
46 Left wall (peripheral wall)
48 Right wall (peripheral wall)
50 Battery module (battery)
80A, 80B lower arm (suspension lower arm)
84 Under member (shock absorber)
86 Lower reinforcement (shock absorber)
120 floor panels (car floor)
122 rocker

Claims (4)

A case main body portion, which is disposed on the vehicle lower side of the passenger compartment floor, has a bottom wall and a peripheral wall extending from the peripheral edge portion of the bottom wall to the vehicle upper side, and is capable of accommodating a battery therein,
A front extending portion integrally formed with the case main body from the peripheral wall on the vehicle front side of the case main body to the vehicle front side of the case main body;
A shock absorbing portion that extends in the vehicle front-rear direction, the rear end portion is connected to a vehicle front side portion of the front extension portion, and is deformed by input of a collision load from the vehicle front,
Vehicle substructure provided with.   The vehicle underbody structure according to claim 1, wherein the case body is connected to rockers extending in the vehicle front-rear direction on both sides of the case body in the vehicle width direction.   The vehicle lower part structure according to claim 1 or 2, wherein a pair of left and right suspension lower arms are swingably attached to both ends of the front extension in the vehicle width direction. 4. The vehicle lower portion according to claim 1, wherein the shock absorbing portion includes a pair of left and right undermembers extending in the vehicle front-rear direction and an underreinforce connecting the front ends of the undermembers. Construction.